JP6854953B1 - Wire electric discharge machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire electric discharge machining apparatus having high accuracy by suppressing a deviation of a relative position of an upper guide unit caused by a temperature change with a simple and minimum improvement. SOLUTION: The wire electric discharge machine 100 includes an upper support 6 for supporting an upper guide unit 82 that guides a wire electrode W on the upper side, and the upper support 6 is provided with an upper guide unit 82 at the lower end. The arm 61, the shaft drive portion 51 formed of a material having a linear expansion coefficient larger than that of ceramics while moving the arm 61 in at least one axial direction, and the arm 61 and the shaft drive portion 51 are connected and formed of ceramics. The adjustment block 62 is provided at a position where the displacement of the upper guide unit 82 due to expansion and contraction of the upper support 6 is suppressed due to the bimetal effect generated on the fastening surface between the shaft drive unit 51 and the adjustment block 62. It is characterized by being. [Selection diagram] Fig. 2

Description

The present invention relates to a wire electric discharge machine that performs electric discharge machining using a wire electrode, and in particular, from an upper support that supports an upper guide unit that extends laterally from a column extending vertically and guides the wire electrode on the upper side, and from the column. The present invention relates to an electric discharge machine including a lower support that supports a lower guide unit that extends laterally and guides a wire electrode on the lower side.

Conventionally, a wire electric discharge machine for electric discharge machining of an workpiece using a wire electrode is known. Since the wire electric discharge machine processes by utilizing the electric discharge phenomenon between the workpiece and the wire electrode, it is possible to precisely process high hardness materials such as hard metals and ceramics that are difficult to cut by cutting. it can.
In recent years, high-hardness materials have come to be used for various parts such as dies from the viewpoint of improving durability, and wire electric discharge machines are required to realize a high level of machining accuracy. ..

In a general-purpose wire electric discharge machine, an upper guide unit and a lower guide unit are attached to the tips of an upper support and a lower support that are supported so as to be arranged horizontally from the column side, respectively. However, the upper support is generally formed to include one or more components including an arm and a shaft drive portion in the overall configuration of the wire electric discharge machine. When machining an workpiece in a wire electric discharge machine, a wire electrode is placed between the upper wire guide housed in the upper guide unit and the lower wire guide housed in the lower guide unit. The upper guide unit and the lower guide unit are moved relative to the workpiece while being stretched with a predetermined tension and generating an electric discharge in the machining gap formed between the traveling wire electrode and the workpiece. By doing so, the workpiece is cut into an arbitrary shape. Further, by controlling the relative positions of the upper guide unit and the lower guide unit, it is possible to perform so-called taper cutting in which the wire electrodes are arranged at a desired angle and discharged to process the workpiece into a precise shape. Is.

In such a wire electric discharge machine, the upper support and the lower support are deformed due to various factors, and an error is given to the positioning accuracy of the upper guide unit or the lower guide unit attached to the tip. For example, for external force, the error is reduced by using a highly rigid material. Further, for thermal displacement, an error is reduced by using a material having a smaller coefficient of thermal expansion. However, when the temperature of the device rises or falls due to heat generation or changes in the temperature of the external environment, a difference in thermal expansion due to thermal displacement occurs on the fastening surfaces of components made of different materials, which may adversely affect machine accuracy and machining accuracy. is there. Specifically, when the temperature of the upper guide unit and the support supporting the lower guide unit changes, the support expands or contracts to cause thermal deformation, and the relative between the upper guide unit and the lower guide unit. There has been a problem that misalignment occurs and causes deterioration of positioning accuracy and machining accuracy.

In order to prevent thermal displacement of component parts, a processing liquid is known to be circulated through upper and lower supports (Patent Document 1). Specifically, the processing liquid is circulated inside so as to control the upper support and the lower support that support the wire electrode to the same temperature, and the upper and lower supports are always kept at the same temperature. As a result, the expansion and contraction of both are the same, so that deterioration of processing accuracy can be prevented.
In addition, there is also one in which a plurality of temperature detection sensors for detecting the temperature are arranged in the main body of the device, and the amount of thermal deformation of the device is calculated based on the temperature detected by the temperature detection sensor when wire discharge processing is performed to correct the amount of movement (the amount of movement is corrected). Patent Document 2).
Furthermore, a wire electric discharge machine that selects the horizontal length of each component so that the amount of change due to temperature change of the upper support and the amount of change due to temperature change of the lower support are equal in consideration of the difference in material. (Patent Document 3) and the like are disclosed.

Jikken Sho 63-42881 Japanese Unexamined Patent Publication No. 62-176735 Japanese Patent No. 5922995

However, the method of distributing the processing liquid inside the apparatus as in Patent Document 1 increases the size of the apparatus and requires the circulation equipment cost and the maintenance cost of the processing liquid. Further, the method of using the temperature detection sensor as in Patent Document 2 requires the purchase cost of additional parts such as the temperature detection sensor, and further, if the accurate temperature of the apparatus main body cannot be measured in real time, a time lag occurs in the correction value. There may be an error in the correction.

Therefore, as a result of diligent studies by the inventors of the present application based on the invention disclosed in Patent Document 3, an upper support that is simple, low cost, and minimizes thermal displacement is obtained by devising a structure. I came to invent.

Therefore, an object of the present invention is to provide an electric discharge machining apparatus capable of improving positioning accuracy and machining accuracy with a simple configuration and low cost.

The present invention is a wire electric discharge machine provided with an upper support that supports an upper guide unit that guides a wire electrode on the upper side, and the upper support includes an arm provided with the upper guide unit at the lower end. A shaft drive unit provided on the back surface of the arm and formed of a material having a linear expansion coefficient larger than that of ceramics while moving the arm in at least one axial direction is connected to the arm and the shaft drive unit and ceramics. The adjustment block is fixed at a position where the displacement of the upper guide unit due to the expansion and contraction of the upper support is suppressed by the bimetal effect generated on the fastening surface between the shaft drive unit and the adjustment block. It is characterized by being done.

Here, the "axis drive unit" is a drive mechanism for moving the arm in the axial direction, and refers to a drive mechanism in which at least the arm is fixed via an adjustment block. Specifically, in this embodiment, at least a U-axis slider is included.
When the temperature of the upper support changes, the entire upper support expands and contracts, causing a relative misalignment between the upper guide unit and the lower guide unit. Therefore, by fixing the arm and the shaft drive unit via the adjustment block instead of directly fixing them, the bimetal effect generated in the arm and the shaft drive unit made of different materials is utilized, and the direction is opposite to the expansion / contraction direction of the upper support. It is possible to generate a displacement in the direction, and as a result, suppress the relative positional deviation between the upper guide unit and the lower guide unit.

The wire electric discharge machine of the present invention is characterized in that the upper surface of the adjustment block is fixed to the bottom surface of the shaft drive unit.

As the structure of the present invention, the upper surface of the adjustment block made of ceramics is fixed to the bottom surface of the shaft drive unit made of a material having a coefficient of linear expansion larger than that of ceramics, and the arm is directly fixed to the shaft drive unit. Not. With such a structure, the bimetal effect generated on the fastening surface between the adjustment block and the shaft drive unit causes the upper guide unit to be displaced in the opposite direction to the expansion and contraction direction due to the temperature change of the upper support, and the upper guide is provided. It is possible to eliminate the displacement of the unit.

The wire electric discharge machine of the present invention is characterized in that the adjusting block is provided so as to project from the back surface of the arm.
Further, the wire electric discharge machining apparatus of the present invention is characterized in that the arm and the adjusting block are integrally molded.
Further, the wire electric discharge machine of the present invention is characterized in that the arm and the adjusting block are formed in an inverted L shape as a whole in a side view.

According to the present invention, there is a simple configuration and low cost, such as a configuration in which the adjustment block is provided so as to project from the back surface of the arm, or a configuration in which the arm and the adjustment block are formed in an inverted L shape in a side view as a whole. It is possible to suppress the relative positional deviation between the upper guide unit and the lower guide unit.
Further, by integrally molding the adjustment block and the arm, the manufacturing process can be simplified.

In the wire electric discharge machine of the present invention, an adjustment block made of ceramics is simply placed on a shaft drive unit made of a material having a coefficient of linear expansion larger than that of ceramics, and an upper guide is provided by thermal expansion or contraction of the upper support. It is possible to minimize the displacement of the unit, suppress the relative position deviation caused by the temperature change at a simple and low cost, and provide a highly accurate wire electric discharge machining apparatus.

It is a side view which shows the outline of the wire electric discharge machining apparatus 100 which concerns on embodiment of this invention. It is a perspective view which shows the embodiment of the upper support 6 of the said embodiment. It is a side view which shows the embodiment of the upper support 6 of the said embodiment. It is a bottom view which shows the embodiment of the upper support 6 of the said embodiment. It is a schematic diagram which shows the adjustment block 62 of the said embodiment. It is explanatory drawing which shows the displacement of the conventional upper support 500 when the outside air temperature rises. It is explanatory drawing which shows the displacement of the upper support 6 of this invention when the outside air temperature rises. It is a side view which shows the other example of the upper support 6 of the said embodiment. It is explanatory drawing which shows the vertical displacement [μm] by the temperature change [° C.] of the external environment of the upper support 6 of the said embodiment. It is a perspective view which shows the conventional upper support body 500.

<1. First Embodiment>
(1.1 Overall configuration of wire electric discharge machine 100)
Hereinafter, the first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view showing an outline of a wire electric discharge machine 100 according to an embodiment of the present invention, and FIG. 2 is a perspective view showing an embodiment of an upper support 6 of the above embodiment. FIG. 3 is a side view showing an embodiment of the upper support 6 of the above embodiment. In the following description, in the machine machine of the wire electric discharge machine 100, the surface on the side where the vertical arm 61 is provided on the U-axis slider 51 (the surface when the machine machine is viewed from the left side on the paper surface of FIG. 1). Is the front. The rear side faces the front, and the right-hand side and the left-hand side face the front. Then, the surface when the machine is viewed from the upper side when facing the front is the upper surface, and the surface when the machine is viewed from the lower side is the bottom surface.

The wire discharge processing apparatus 100 includes a bed 1 mounted on an installation surface, a column 2 installed on the bed 1 so as to be reciprocally movable in the horizontal Y-axis direction, and a Y-axis direction on the column 2. A V-axis slider 52 installed horizontally so as to be able to reciprocate in a horizontal one-axis direction (V-axis direction) parallel to the above, a Z-axis base 91 provided at one end of the V-axis slider 52, and linear to the Z-axis base 91. A Z-axis slider 93 attached so as to be reciprocally movable in the Z-axis direction via a guide 93a, and a horizontal 1 parallel to the X-axis direction via a linear guide 51a on a surface of the Z-axis slider 93 facing the Z-axis base 91. It includes a U-axis slider 51 horizontally installed so as to be reciprocally movable in the axial direction (U-axis direction), a vertical arm 61, and an adjustment block 62 fixed to the bottom surface of the U-axis slider 51.
Here, the vertical arm 61, the adjustment block 62, the U-axis slider 51, and the Z-axis slider 93 are collectively referred to as the upper support 6.
The upper guide unit 82 is fixed to the lower end of the vertical arm 61, the lower support 7 extending from the column 2 is fixed to the lower side wall of the column 2, and the lower guide unit 81 is fixed to one end. ing.

Further, a table 3 is provided so as to be movable in a direction perpendicular to the Y-axis direction (X-axis direction), and a processing tank 4 (not shown) is mounted on the table 3, and a workpiece is placed on the work in the processing tank 4. It can be placed on a stand.

A plurality of rails 11 extending in the Y-axis direction and a plurality of rails 13 extending in the X-axis direction are fixed to the upper portion of the bed 1, and the rails 11 engage with a plurality of linear guides 21 fixed to the bottom of the column 2. , The rail 13 is engaged with a plurality of linear guides 31 fixed to the bottom of the table 3. As a result, the column 2 can move linearly in the Y-axis direction, and the table 3 can move linearly in the X-axis direction.

A plurality of rails 22 extending in the V-axis direction are fixed to the upper portion of the column 2, and these rails 22 are engaged with a plurality of linear guides 52a fixed to the bottom of the V-axis slider 52. As a result, the V-axis slider 52 can move linearly in the V-axis direction.
A Z-axis base 91 is integrally fixed to one end of the V-axis slider 52.

A plurality of rails 92 extending in the Z-axis direction are fixed to the front surface of the Z-axis base 91, and these rails 92 are engaged with a plurality of linear guides 93a provided on the Z-axis slider 93. As a result, the Z-axis slider 93 can move linearly with respect to the Z-axis base 91 in the vertical direction, that is, in the Z-axis direction.

A plurality of rails 94 extending in the U-axis direction are fixed to the front surface of the Z-axis slider 93, and these rails 94 are engaged with a plurality of linear guides 51a provided on the U-axis slider 51. As a result, the U-axis slider 51 can move linearly with respect to the Z-axis slider 93 in the U-axis direction.

As the linear guides 21, 31, 51a, 52a, 93a, known ones can be appropriately used, and the column 2, the U-axis slider 51, the V-axis slider 52, the Z-axis slider 93, and the table 3 are driving members such as a motor. Moves back and forth in each direction.

The U-axis slider 51 is a member having a substantially rectangular shape in a side view. The V-axis slider 52, the Z-axis base 91, the Z-axis slider 93, and the U-axis slider 51 are made of cast iron, which is a material having a larger coefficient of linear expansion than ceramics due to manufacturing restrictions.

The vertical arm 61 is a long prismatic member, the adjusting block 62 is fixed to the back surface, and the upper guide unit 82 made of stainless steel is provided at the lower end. The vertical arm 61 is provided perpendicular to the XY plane and is made of ceramics, which is a highly rigid material with little deformation due to heat.

The lower support 7 is a prismatic or cylindrical member fixed to the lower part of the front surface of the column 2 and extending from the column 2, and the lower guide unit 81 is fixed to the tip thereof. The lower support 7 is made of ceramics, and the lower guide unit 81 is made of stainless steel, which is a material having a coefficient of linear expansion larger than the coefficient of linear expansion of cast iron.

The wire electric discharge machine 100 supplies a machining voltage to the work piece and the wire electrode W from a power supply device for electric discharge machining (not shown), and uses a control device (not shown) to raise the work piece placed on the work stand. Electric discharge machining can be performed by relatively moving the wire electrode W spanned between the guide unit 82 and the lower guide unit 81 along a desired path.

(1.2 Configuration of adjustment block 62)
FIG. 4 is a bottom view showing an embodiment of the upper support 6 of the above embodiment, and FIG. 5 is a schematic view showing an adjustment block 62 of the above embodiment. FIG. 6 is an explanatory diagram showing the displacement of the conventional upper support 500 when the outside air temperature rises, and FIG. 7 is an explanatory diagram showing the displacement of the upper support 6 of the present invention when the outside air temperature rises. FIG. 8 is a side view showing another example of the upper support 6 of the above embodiment, and FIG. 10 is a perspective view showing a conventional upper support 500. Here, in FIGS. 6 and 7, the vertical arms 61, 561 and the adjustment block 62 are shown by diagonal lines for easy understanding.
In the conventional wire electric discharge machine, the vertical arm 561 is fixed to the fastening surface M1 parallel to the XZ surface and to the U-axis slider 551 (FIGS. 6 and 10). When the temperature of the upper support 500 changes due to a change in the external environment, the entire upper support 6 expands in the front direction (negative direction in the Y-axis direction) or contracts in the back direction (positive direction in the Y-axis direction) (F3). ), The upper guide unit 582 provided at the lower end of the vertical arm 561 also shifts in the front direction or the back direction as the upper support 500 expands and contracts, and the relative positions of the upper guide unit 82 and the lower guide unit 81 shift. appear. This is because the Z-axis slider 93 and the U-axis slider 51 constituting the upper support 6 are made of cast iron, which is a material having a coefficient of linear expansion larger than that of ceramics in manufacturing, so that the lower support made of ceramics is used. This is because it expands and contracts more than the body 7.
Further, internal stress is generated in the fastening surface M1 due to the difference in the coefficient of thermal expansion due to the difference in the materials of the U-axis slider 551 and the vertical arm 561 (bimetal effect). Specifically, the ceramics, which is the material of the vertical arm 561, has a linear expansion coefficient of about 1/2 to about 1/3 as compared with the cast iron, which is the material of the U-axis slider 551. The compression and tensile stress acting in parallel with M1 become large, a force F1 tilting from the vertical direction is generated on the vertical arm 561, and the upper guide unit 82 is displaced in the front direction. Further, when the temperature drops, a force opposite to the force F1 that inclines from the vertical direction is generated on the vertical arm 561, and the upper guide unit 582 shifts toward the back surface.
In this way, due to the two factors of expansion and contraction due to the heat of the upper support 6 and the bimetal effect of the U-axis slider 551 and the vertical arm 561, the upper guide unit 582 shifts toward the front when the temperature rises, and moves toward the back when the temperature drops. It will shift.

Therefore, in the present embodiment, the upper surface 621 of the adjustment block 62 (FIGS. 4 and 5) made of ceramics having a coefficient of thermal expansion smaller than that of cast iron is fixed to the bottom surface of the fastening surface M2 of the U-axis slider 51 for adjustment. The vertical arm 61 is fixed to the front surface 623 of the block 62. The U-axis slider 51 and the vertical arm 61 are indirectly connected via the adjustment block 62, and are not directly connected to each other.
With such a structure, when the temperature rises, the entire upper support 6 extends in the front direction (negative direction in the Y-axis direction) due to heat (F3), but the bimetal of the U-axis slider 51 and the adjustment block 62. Due to the effect, a force F2 tilting in the back direction (positive direction in the Y-axis direction) acts on the vertical arm 61, and the deviation of the upper guide unit 82 can be offset (FIG. 7). When the temperature drops, the entire upper support 6 contracts in the rearward direction (positive direction in the Y-axis direction), but due to the bimetal effect of the U-axis slider 51 and the adjustment block 62, the upper support 6 is in the front direction with respect to the vertical arm 61 (in the front direction). Since a force that tilts in the negative direction in the Y-axis direction acts, the deviation of the upper guide unit 82 can be offset.
Even when the temperature of the upper support 6 rises or falls, it is possible to eliminate the deviation of the upper guide unit 82 by improving the simple structure of adding the adjusting block 62.

Although the shape of the adjustment block 62 is square in the present embodiment (FIG. 5), the upper side due to the expansion and contraction of the upper support 6 by utilizing the bimetal effect generated on the fastening surface M2 of the U-axis slider 51 and the adjustment block 62. The shape is not limited as long as it can cancel the deviation of the guide unit 82, and may be, for example, a columnar shape. By changing the shape and size of the adjusting block 62, the effect of the bimetal generated on the fastening surface M2 can be adjusted, and the amount of inclination of the vertical arm 61 can be determined.
The material of the adjusting block 62 may be any material having a smaller coefficient of thermal expansion than the material used for the U-axis slider 51, and is preferably ceramic.
Further, the mounting position of the adjustment block 62 to the U-axis slider 51 is such that the upper guide unit 82 is displaced due to the expansion and contraction of the upper support 6 by utilizing the bimetal effect generated on the fastening surface M2 of the U-axis slider 51 and the adjustment block 62. It is not particularly limited as long as it is a position where can be offset.
The adjustment block 62 may be provided, for example, so as to project from the back surface of the vertical arm 61 (FIG. 3), or the vertical arm 61 and the adjustment block 62 may be formed in an inverted L shape as a whole in a side view. Good (Fig. 8).
Further, the vertical arm 61 and the adjustment block 62 may be integrally molded.

<2. Simulation example>
FIG. 9 is an explanatory diagram showing a vertical displacement [μm] of the upper support 6 of the above embodiment due to a temperature change [° C.] of the external environment.
A numerical simulation was performed to compare the effects of the upper support 6 according to the present embodiment and the conventional upper support 500 (Comparative Example 1, FIG. 6, FIG. 10) having no adjustment block 62.
Specifically, the state in which the outside air temperature (room temperature) of the upper support 6,500 is raised by 3 ° C. and the state in which the temperature is raised by 6 ° C. is repeated (graph at the bottom of FIG. 9), and the upper side attached to the vertical arm 61 is attached. The displacement [μm] of the guide units 82 and 582 in the vertical direction (Z-axis direction) was measured (upper graph in FIG. 9). Here, in the upper graph of FIG. 9, the solid line is a graph showing the vertical displacement [μm] of the upper support 6 according to the embodiment of the present invention, and the broken line is the vertical of the conventional upper support 500 of Comparative Example 1. It is a graph which shows the displacement [μm].

According to the upper graph of FIG. 9, as compared with the upper support 500 of Comparative Example 1, the upper support 6 having the adjustment block 62 has the upper guide unit 82 even when the temperature of the outside air changes. It can be seen that there is little vertical deviation.
As described above, the upper support 6 has a simple structure in which the adjusting block 62 is attached, so that the warp and deformation of the vertical arm 61 can be suppressed.

In the present embodiment, the upper support 6 is moved in the U-axis, V-axis, Y-axis, and Z-axis directions, and the table 3 is moved in the X-axis direction. However, the table 3 is moved in the Y-axis and X-axis directions. It may be configured to move to.
In the configuration of the present embodiment, the Z-axis slider 93 is provided on the front side of the V-axis slider 52, the U-axis slider 51 is provided on the front side of the Z-axis slider 93, and the vertical arm 61 is provided on the front side of the U-axis slider 51. However, no matter what position the V-axis slider 52, U-axis slider 51, and Z-axis slider 93 are attached to, the shaft drive unit attached to the frontmost side On the other hand, if the vertical arm 61 is arranged on the front side, the same effect can be obtained by using the adjustment block 62.

The present invention described above can be carried out in various other forms without departing from the spirit and essential characteristics of the present invention. Therefore, the examples described herein are exemplary and should not be construed as limited to this.

1 Bed 2 Column 3 Table 51 U-axis slider 52 V-axis slider 6 Upper support 61 Vertical arm 62 Adjustment block 7 Lower support 81 Lower guide unit 82 Upper guide unit 91 Z-axis base 93 Z-axis slider W wire electrode 100 Wire EDM 500 Conventional upper support

Claims (5)

A wire electric discharge machine provided with an upper support that supports an upper guide unit that guides a wire electrode on the upper side.
The upper support is formed of an arm provided with the upper guide unit at the lower end and a material provided on the back surface of the arm, which moves the arm in at least one axial direction and has a coefficient of linear expansion larger than that of ceramics. The shaft drive unit is connected to the arm and the shaft drive unit, and an adjustment block made of ceramics is provided.
The wire is fixed at a position where the displacement of the upper guide unit due to expansion and contraction of the upper support is suppressed by the bimetal effect generated on the fastening surface between the shaft drive unit and the adjustment block. Electric discharge machine. The wire electric discharge machining apparatus according to claim 1, wherein the upper surface of the adjustment block is fixed to the lower surface of the shaft drive unit. The wire electric discharge machining apparatus according to claim 1 or 2, wherein the adjusting block is provided so as to project from the back surface of the arm. The wire electric discharge machining apparatus according to any one of claims 1 to 3, wherein the arm and the adjusting block are integrally molded. The wire electric discharge machining apparatus according to any one of claims 1 to 4, wherein the arm and the adjusting block are formed in an inverted L shape as a whole in a side view.

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